It is a well recognized fact that many elderly or impaired people require a walking aid for rehabilitation or locomotion purposes. The standard "walker" is a device having four legs, which are lifted and advanced by the user, with the user advancing one or more steps prior to the cycle being repeated.
Some of the deficiencies inherent in the standard "walker" are the fact that the lift-move-set-step operation places an unnatural strain on the users legs, back and arms, and in particular produces a bending movement on the spinal column. The speed of the "walker" is also a problem in that the pace permissible with such a device is usually one-fourth to one-third the normal walking pace. In addition most walkers are notoriously unstable and cannot be used by persons subject to vertigo or having deteriorated joints. During the operation of the walker, it must be lifted and set down a number of times, which requires excellent balance and coordination, since any unusual forces applied to the walker will cause it to tip over thereby toppling the user. Furthermore, the standard walker is not particularly rehabilitative, since it does not encourage normal walking due to the slow speeds and unusual manipulations, which the user is forced to endure while operating the device.
Because of the disadvantages of a standard walker listed supra, an attempt was made to develop an improved device. It was obvious that such an improved device should incorporate the following list of desirable performance features and properties:
It should have a low center of mass and a high resistance to tipping in any direction.
It should have sufficient stability so that it can be relied on 100 percent of the time during walking. Hand grips would provide a smooth, perdictable trajectory, and these grips would be relied upon in case the user trips, stumbles, or loses balance.
The mass of the device would be small enough to make stopping easy, and a braking system would be incorporated as a stopping aid.
It should allow the user to attain normal walking speeds, or any speed less than normal walking speed at which the user is comfortable.
No lifting forces of any kind should be required.
The device should have minimum protrusions around the user so that it is maneuverable, and the periphery of the device would be padded so that the effect of a collision would be minimized.
Finally, the device should encourage and promote rehabilitation.
Examples of prior art devices which unsuccessfully attempted to meet the above stated criteria can be seen by reference to the following U.S. Pat. Nos. 4,116,464; 3,165,314; 2,872,967; 1,448,783 and 1,307,058.
The present invention is based around the idea of modifying a standard wheelchair in such a manner that the wheelchair in effect becomes a walking device.
To this end a wheelchair was purchased, analyzed, and then modified. The modifications were such that the flexing chassis of the wheelchair, which allows it to maintain all four wheels on uneven floors, was not comprised. The modifications comprised: the addition of mass at the base toward the front wheels, to lower the overall center of mass and reduce the possibility of tipping; the addition of an "equal-force" braking system to aid the user in stopping the system, with a straight trajectory; the removal of the footrests to reduce protrusions on the forward end of the wheelchair; and the addition of padding at the front of the wheelchair to reduce the probability and consequences of a collision.
With these modifications, the wheelchair possessed the desirable properties that the improved walker should have.
In addition there were several unforeseen benefits to the user that result from using the modified wheelchair as a walker since the seating capability and the normal function of the wheelchair are not lost, the user may use the seat; to transport items; to rest between walking sessions; to move the chair from a seated position between walking sessions; to sit in the chair at a destination; or to give aid to another person by having that person ride the chair while it is being pushed. Because wheelchairs are familiar to most of the population, learning time and acceptance problems should be minimized.
The steering and handling capabilities of wheelchairs are well-developed and predictable. Also, the large rear wheels tend to reduce problems associated with floor or pavement irregularities. Advantage could also be taken of the existing mass-production capability for wheelchairs, to minimize cost to each user. Finally since current building codes now require ramp entrances and elevators in public buildings, these codes favor the use of a wheelchair as a walker.
Some of the potential applications of the instant invention are: as a relatively permanent walking aid for the elderly, replacing the poorly designed standard walker; as a temporary or permanent walking aid for persons with dizziness and other equilibrium problems; as a rehabilitation and therapy device for many types of leg and hip injuries, including muscle and joint problems as well as fractures, strains and sprains; and a rehabilitation device for a variety of post-operative conditions in which the patient must get up and walk as soon as possible, to avoid complications.